Kaneta Tomohiro, Wada Motoshi, Takanami Kentaro, Ishii Tomohiro, Matsumoto Setsu, Okada Ken, Fukuda Hiroshi, Yamada Shogo, Takahashi Shoki
Department of Diagnostic Radiology, Graduate School of Medicine, Tohoku University, 1-1 Seiryomachi, Aoba-ku, Sendai 980-8574, Japan.
Ann Nucl Med. 2007 Dec;21(10):597-601. doi: 10.1007/s12149-007-0072-5. Epub 2007 Dec 25.
The correct estimation of the portosystemic shunt (PSS) ratio prior to surgery for patent ductus venosus is important. Until now, formulas using the lung and liver uptake for per-rectal portal scintigraphy using 123I-iodoamphetamine (IMP) have been mainly used for calculating the PSS ratio. However, these methods did not take radioactivity in the brain or changes in organ radioactivity over time into consideration. Here, we performed sequential whole-body scanning by per-sigmoid colon 123I-IMP scintigraphy, and evaluated the changes in radioactivity in the liver, lungs, and brain over time.
The patient was 7-year-old boy with a patent ductus venosus. A 10 Fr. catheter was inserted into the sigmoid colon under fluoroscopic guidance, through which about 55.5 MBq of 123I-IMP was administered. Following the administration, the patient was placed in the supine position and sequential whole-body scanning (from head to thigh) was performed for up to about 80 min. Four regions of interest (ROIs) were placed on the whole brain, lungs, liver, and mediastinum. The PSS ratios were calculated using both the traditional formula (PSS index: brain uptake is not considered) and our original formula (new index: brain uptake is considered).
Prior to surgery, the radioactivity could be seen clearly in the brain and lungs just following the injection. The liver uptake was faint on the first and second scans (15 min/scan), and increased gradually over time. In contrast, almost no radioactivity was detected in the brain or lungs following surgery. The liver uptake could be seen clearly just following the injection. The new index was significantly higher than the PSS index. Both the new index and the PSS index showed changes over time especially prior to surgery.
Distinct brain radioactivity was observed early following administration in a patient with PSS. The calculation of the PSS fraction should be performed taking the brain radioactivity into consideration. The timing of the scan should be fixed, but 30 min following administration may be too early to begin scanning.
在静脉导管未闭手术前准确估算门体分流（PSS）比值很重要。到目前为止，主要使用利用123I-碘安非他明（IMP）经直肠门静脉闪烁显像的肺和肝摄取量的公式来计算PSS比值。然而，这些方法未考虑脑内放射性或器官放射性随时间的变化。在此，我们通过经乙状结肠123I-IMP闪烁显像进行连续全身扫描，并评估肝脏、肺和脑内放射性随时间的变化。
患者为一名7岁患有静脉导管未闭的男孩。在荧光透视引导下将一根10 Fr.的导管插入乙状结肠，通过该导管注入约55.5 MBq的123I-IMP。给药后，患者仰卧，进行连续全身扫描（从头至大腿），持续约80分钟。在全脑、肺、肝脏和纵隔上放置四个感兴趣区（ROI）。使用传统公式（PSS指数：不考虑脑摄取）和我们的原始公式（新指数：考虑脑摄取）计算PSS比值。
手术前，注射后即刻可在脑和肺中清晰看到放射性。肝脏摄取在第一次和第二次扫描（每次扫描15分钟）时较淡，随时间逐渐增加。相比之下，手术后在脑或肺中几乎未检测到放射性。注射后即刻可清晰看到肝脏摄取。新指数显著高于PSS指数。新指数和PSS指数均随时间变化，尤其是在手术前。
在患有PSS的患者中，给药后早期观察到明显的脑放射性。计算PSS分数时应考虑脑放射性。扫描时间应固定，但给药后30分钟开始扫描可能太早。
